Boom construction for ditching machine



April 10, 1962 G. E. MALZAHN BOOM CONSTRUCTION FOR DITCHING MACHINEFiled April 14. 1960 2 Sheets-Sheet 1 WW I 605 E Ma/za/m IN VENTOR.

April 10, 1962 G. E. MALZAHN 3,028,693

BOOM CONSTRUCTION FOR DITCHING MACHINE Filed April 14, 1960 2Sheets-Sheet 2 United States Patent 3,028,693 BOOM CONSTRUCTION FORDITCHING MACHINE Gus E. Malzahn, P.O. Box 66, Perry, Okla. Filed Apr.14, 1960, Ser. No. 22,317 Claims. (Cl. 37-86) This invention relates toportable ditch or trench digging machines having a boom assemblyadjustably mounted thereon and extending therefrom for supportingcontinuously moving digging tools used for various earth movingpurposes.

It is therefore a primary object of this invention, to provide a boomassembly which is of simple construction, and having readily replaceableparts capable of being easily disassembled for repair purposes.

It is a further object of this invention, to provide a boom constructionwhich is both laterally and torsionally rigid but longitudinallyyieldable as desired, less susceptible to damage and therefore has awider and greater utility.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevational view of the boom assembly as mounted on aditch trencher machine.

FIGURE 2 is a perspective view of the front sprocket supportingassembly.

FIGURE 3 is a partial side elevational view of the boom assembly, withparts shown in section.

FIGURE 4 is a partial top plan view of the boom assembly.

FIGURE 5 is a transverse sectional view taken through a plane indicatedby the section line 5-5 in FIGURE 1.

Referring to FIGURE 1, the boom assembly generally indicated byreference numeral is shown mounted on a ditch trencher machine indicatedby reference numeral 12 as is generally known in the art. The boomassembly slidably supports at its front end a front sprocket assembly orwork thrust engaging means generally indicated by reference numeral 14while the main supporting assembly 16 supports intermediate its length asprocket assembly 18 while a chain 21 carrying a plurality of spaceddigging tools 22 is trained around the sprockets supported by thesprocket assemblies, and is driven by power means located on the machine12. The main boom assembly 16 is adjustably pivoted to the machine 12,for downward movement into various digging positions and upwardlymovable when retracted.

Referring now to FIGURE 2, the front bracket assembly 14 includes asprocket carrying bracket 24 having ears 26 and 28 having aligned holes36 and 32 for journaling a sprocket wheel therebetween. A shank 34 issecured to the bracket 24 and has an enlarged portion 36 at its innerend for reasons which will hereafter become apparent.

As more clearly seen in FIGURES 3 and 4, the main boom assembly portion16 includes a tubular member 38 within an open end of which the frontsprocket assembly is slidable, the tubular member having secured theretoby welding or other equivalent means the sprocket assembly 18 consistingof a supporting sprocket bracket 40 depending downwardly therefrom forrotatably supporting a sprocket or transmitting wheel 42. A sprocket ortransmitting wheel 44 is also rotatably mounted by the cars 26 and 28 ofbracket 24 and the endless chain 20 is trained about sprocket wheels 42and 44. As more clearly seen in FIGURE 5, the tubular member 38 is ofrectangular cross-section so as to better resist bending in both avertical and horizontal plane.

As clearly seen in FIGURES 3, 4 and 5, the shank 34 of the frontsprocket assembly is slidably disposed within the tubular member 38 andis biased outwardly therefrom by means of a coil spring 46 reactingbetween the enlarged end portion 36 of shank 34 and a pin 48transversely disposed between opposite side walls of the tubular member38 and secured thereto as by welding 50 as seen in FIGURE 4. In order toslidably guide the narrow portion of shank 34 and limit outward movementof the shank, plates 52 and 54 are provided within the outer end of thetubular member 38 against the inner walls thereof. The plates 52 and 54are secured to the tubular member 38 by welding 56 as more clearly seenin FIGURES 3 and 4. The plates 52 and 54 accordingly limit outwardmovement of the shank 34 by abutting against the shoulders formed byenlarged portion 36 of the shank and furthermore seal the open end ofthe tubular member 38.

From the foregoing description, it is therefore ap parent that the boomassembly 10 is capable of'yielding inwardly when overloaded by thedigging tools 22, by virtue of the spring 46 reacting between pin 48 inthe tubular member and the end of the shank slidable therein. It is alsoapparent that the spring 46 is protected from damage by the earth beingmoved, since it is entirely enclosed within the tubular member 38 andsealed therein by the plates 52 and 54 at its open end which alsoslidably guide the shank 34 and limit its outward movement. Also, sincethe plates are secured to the tubular member 38 only at its outerexposed end by welding 56 which may be readily cut, the boom assemblymay be easily disassembled for repair purposes.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be resorted to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

1. In a ditch trencher machine, a digging boom assembly adjustablymounted on said machine extending outwardly and forwardly of saidmachine, said boom assembly comprising an elongated tubular member ofrectangular cross-section, a sprocket supporting bracket having parallelears for rotatably supporting a sprocket wheel therebetween, a shanksecured to said bracket and slidably disposed within said tubular memberat an outer end thereof, said shank having an enlarged cross-section atan inner end portion thereof slidable relative to inner walls of saidtubular member and spaced from a pin mounted in said tubular member andextending transversely between said inner walls, spring means disposedwithin said tubular member and abutting between said pin and said innerend portion of said shank, separate plates disposed against the innerwalls of said tubular member adjacent its outer end, for slidablyguiding said shank and limiting its outward movement by engagement withthe enlarged inner end portion, said plates being secured to saidtubular member by welding at its outer end, a second bracket rigidlysecured to said tubular member intermediate its length extendingdownwardly and perpendicular thereto for rotatably mounting a sprocketand an endless chain drivingly engaged with said sprocket wheel andsprocket, carrying a plurality of spaced digging tools.

2. In a ditching machine, a digging boom assembly mounted on saidmachine and extending outwardly therefrom, said boom assembly comprisingan elongated tubular member, a bracket having a sprocket wheel rotatablymounted thereon, a shank secured to and support ing said bracket andslidably disposed within said tubular member at an outer end thereof,said shank having at an inner end thereof a portion of enlarged crosssection slidably received within said tubular member, a pin mounted insaid tubular member and extending transversely thereof in spacedrelation to said enlarged portion of said shank, spring means disposedin said tubular member and operatively engaging and yieldinglyseparating said pin and said shank, separate plates constitutingcombined means for journalling and retaining said shank in said tubularmember and disposed against the inner walls of said tubular memberadjacent its outer end and against said shank, the inner ends of saidplates being engageable with said enlarged portion for limiting outwardmovement of said shank in said tubular member, means securing the outerends of said plates to the outer ends of said tubular member, an endlesschain drivingly engaged with said sprocket wheel and spaced diggingtools on said chain.

3. The combination of claim 2 including a second bracket rigidly securedto said tubular member intermediate the length of the latter andprojecting perpendicularly therefrom, a sprocket rotatably mounted uponsaid second bracket and engaged by said chain.

4. The combination of claim 2 including a plane surface on said enlargedportion perpendicular to the axis of said shank and disposedperimetrically about the shank at the junction of the latter with saidenlarged portion, said surface constituting an abutment engageable withthe adjacent ends of said plates.

5. The combination of claim 2 wherein each of said plates comprises afiat rectangular member, the adjacent walls of said tubular member andof said shank having flat plane surfaces each complementary to andengaging one of said plates.

References Cited in the file of this patent UNITED STATES PATENTS405,511 Umstead June 18, 1889 2,247,825 Warner July 1, 1941 2,667,709Askue Feb. 2, 1954 2,686,981 Vaughn Aug. 24, 1954 2,702,485 NadhernyFeb. 22, 1955 2,714,262 Malzahn Aug. 2, 1955 2,764,031 Nystrom Sept. 25,1956

